A hostile opponent is someone who is actively opposed to another person or group. This could be in the form of physical or verbal aggression, or even a more subtle form of opposition. The term 'hostile opponent' can be broken down into two words: 'FOE' and 'ENEMY'. A FOE is someone who is actively hostile towards another person or group, while an ENEMY is someone who is actively hostile and has a strong dislike for another person or group.